This invention pertains generally to waterbeds, and more particularly to a waterbed mattress having a baffle structure for preventing excessive undulations of water in the mattress.
Although waterbeds have enjoyed wide popularity in recent years, some persons are disturbed by the wave-like motion or undulations of the water within the mattress. There have been many attempts to reduce the water movement, for example, by employing vertically-extending baffles inside the mattress. Carson in U.S. Pat. No. 3,736,604 describes a waterbed mattress having perforated, freely-swingable vertical flaps to resist excessive motion of fluid within the mattress. In addition, Fogel in U.S. Pat. No. 4,145,780 describes a waterbed mattress having a baffle dampener comprising an upstanding plastic sheet and a horizontal floatation rod.
Improvements in dampening wave motion have been obtained by using horizontally-extending baffles. Such baffles are described in my aforementioned Application Ser. Nos. 95,214, now U.S. Pat. No. 4,345,348, and 201,304 and my U.S. Pat. No. 4,247,962. These horizontally-extending baffles can comprise a pad of buoyant material anchored to the bottom wall of the mattress so that the pad floats between the top and bottom walls. Fogel in U.S. Pat. No. 4,192,031 describes a baffle comprising a horizontally-extending piece of foam anchored to the bottom of the mattress. Although horizontally extending baffles can be effective in reducing water wave motion, baffles welded to a wall of the mattress such as taught by Fogel can form a leak path at the weld due to stresses on the weld.
My U.S. Pat. No. 3,585,356 shows a waterbed mattress having a plurality of solid particles of a material such as Styrofoam.TM. (an expanded synthetic resinous material) floating in the water for dampening shock a waves in the water. Although the particles of Styrofoam.TM. (an expanded synthetic resinous material) can reduce wave motion, if the Styrofoam.TM. (an expanded synthetic resinous material) is provided as a solid block more effective wave reduction results. However, it is difficult to fold a solid block of Styrofoam.TM. (an expanded synthetic resinous material) in a mattress for storage or shipping.
In place of Styrofoam.TM. (an expanded synthetic resinous material), my Application Ser. No. 201,304 describes use of a mass of nonwoven polyester fiber bound together with acrylic resin. This material has been used in waterbed mattresses marketed by Vinyl Products under the tradename Dream Weaver. An advantage of using this material for a baffle is that it can be compacted due to its porosity so that a mattress containing the material can be folded for shipping and storage. However, the material when used by itself in a Dream Weaver mattress has a significant disadvantage; it is more dense than water and thus is in contact with the bottom surface of the mattress, including where the mattress is in contact with a heater. Because the bottom surface adjacent the heater is in contact with the baffle material, hot spots can develop. Such spots can shorten the useful life of the mattress and can lead to water leaks.
Therefore, it is apparent that there is a need for a baffled waterbed mattress that (i) can be folded, (ii) has the advantages of a horizontally-extending baffle, (iii) does not require the baffle to be secured to any of the walls of the mattress, and (iv) has a baffle that floats spaced apart from the bottom wall of the mattress.